The present invention relates to the handling of strip material, such as photographic film, and more particularly to an automatic rethread mechanism for loading film into a takeup magazine for use in a film recorder or the like.
Various mechanisms utilize strip material that is unwound from a first core, processed, and rewound onto a second core. For example, conventional photographic cameras unwind film from a film cassette onto a spool in a camera. After the film is exposed, it is rewound into the film cassette, which is light tight so that the film can be removed from the camera for processing. Reel-to-reel recorders for film and magnetic tape are also well known.
Various autothread mechanisms are known for use in film cameras. Examples of such mechanisms can be found in U.S. Pat. Nos. 3,463,071; 4,572,635; 4,641,936; 4,752,797; 4,841,319; and 4,956,658. Automatic film threading systems for use with film processing equipment are also well known. Examples of such systems can be found in U.S. Pat. Nos. 3,178,124; 4,248,516; 4,641,939; 4,798,375; 4,831,401; and 4,949,114.
A disadvantage of the automatic film threading arrangements known in the prior art is that a special sprocket wheel or film core is necessary in order to automatically receive and wind the film. Thus, it is necessary to unwind the film off of the special core or sprocket wheel before the apparatus using the film can be reloaded. This operation is inconvenient and time consuming, particularly when the apparatus is used in a commercial environment.
One type of apparatus that uses photographic film and would benefit from an improved automatic film rethread mechanism is known as a film recorder. In a conventional film recorder, a light beam from a cathode ray tube ("CRT") or the like is controlled by a deflection system to scan across a stationary frame of photographic film to expose the film with an image. Typically, the images are generated by a computer for the production of slides, transparencies, photographs, or the like. Alternatively, the images can comprise natural images acquired by a scanner or television camera for subsequent processing by a computer.
Known film recorders, such as those sold under the trademark "Solitaire" by Management Graphics, Inc. of Minneapolis, Minn., U.S.A., typically include a light source such as a CRT for producing a beam, a deflection system for scanning the beam across the face of the CRT, a system control and central processor unit ("CPU") for controlling the deflection system, and a camera (i.e., "film transport"). The latter component may include a film transport body, lens, lens mounting assembly, aperture plate, film plate, and film transport mechanism. On a Solitaire film recorder, an image to be recorded is first written on the phosphor of the CRT by deflecting an electron beam in a raster pattern and modulating the intensity of the beam. This process is analogous to the creation of a television picture. Alternatively, the image can be written on the CRT using well known time modulation techniques, wherein the beam intensity is constant but the time the beam is kept at each point is varied depending on the exposure required.
The resulting pattern (the "object image") on the CRT is optically imaged onto photographic film by the film transport, which contains the required optics and mechanism to advance the film to successive frames. Other types of light sources can be substituted for the CRT in a film recorder. Examples include fiber optic sources, lasers, and focused light impinging a rotating drum wherein one or more rotations are completed for each scan line.
Once each frame of film is exposed, it is wound around a film core for storage until a sequence of frames is ready to be photographically processed. A takeup magazine is generally provided for holding the exposed film in a light tight manner, thereby preventing inadvertent reexposure thereof to light, which would ruin the photographic images contained on the film. In the past, the threading of film onto the film core has been a somewhat cumbersome manual process, wherein the free end of a strip of film from a film supply is inserted into a slot or grip on the film core, and wound around the film core to a point at which rotation of the film core will wind the film around the core without slipping. The manual loading of film in this manner is inconvenient and can reduce productivity.
It would be advantageous to provide an automatic mechanism for threading strip material, such as photographic film, around a takeup spool and/or into a takeup magazine. It would be further advantageous for such apparatus to use a standard film core, without modification and which can be easily removed and replaced with an empty core for use with a subsequent strip of material. Such apparatus should be simple to manufacture and use, and provide highly reliable operation.
The present invention provides a takeup magazine and apparatus for automatically loading strip material around a takeup spool and/or into a magazine having the aforementioned advantages.